Boat hull with outboard drive and outboard drive for boats

ABSTRACT

Boat hull with outboard drive unit, said drive unit ( 5 ) comprising an underwater housing ( 6 ) mounted on the outside of the hull bottom ( 1 ) and a gear housing ( 11 ) mounted on the inside of the hull bottom and joined to the underwater housing. Between the underwater housing and the gear housing there is fixed a mounting plate ( 20 ), which, together with a screw-down plate ( 24 ), with elastic ring ( 23, 27 ) inserts, fixes the drive unit to a flange ( 4 ), which is made on the inside of a well ( 3 ) surrounding an opening ( 2 ) in the hull bottom.

The present invention relates to a boat hull with an outboard drive unitfor at least one propeller, said drive unit comprising an underwaterhousing extending down from the outside of the hull bottom, and an atleast substantially vertical drive shaft being rotatably mounted in saidunderwater housing, extending through an opening in the bottom of thehull and driving, via a bevel gearing enclosed in said underwaterhousing, at least one at least substantially horizontal propeller shaftmounted in said underwater housing

The invention relates also to an outboard drive unit for boats fordriving at least one propeller, comprising, firstly, an underwaterhousing in which there is rotatably mounted a drive shaft, which issubstantially vertical in the operating state of the drive unit, andsaid drive shaft being drivably coupled via a bevel gearing at a lowerend to at least one propeller shaft mounted in the underwater housing,and, secondly, a gearing housing joined to the underwater housing andcomprising a second bevel gearing, via which the upper end of saidessentially vertical drive shaft is drivably coupled to a substantiallyhorizontal shaft, and mounting means for mounting the drive unit withthe underwater housing on the outside and the gearing housing on theinside of a boat hull.

Previously known outboard drive units of the type presently in question,which have a leg or underwater body extending down from the underside ofthe hull bottom, have been mounted in two different manners. In onecase, the leg is rigidly joined to the engine and extends through anopening in the hull bottom, with a rubber bellows or the like forming aseal between the leg and the edge of the surrounding opening. Thepushing forces of the propeller are taken up by the engine and theengine mounting. In the second case, the leg or the underwater housingis fixed to a plate which is screwed securely, or fixed in some othermanner, to the bottom of the hull. In this case the entire propellerforce can be taken up by the hull or a portion can be taken up by thehull and a portion by the drive unit mounted on the inside of the hull,i.e. the engine and transmission.

Common to both alternatives is that the mounting work is relativelycomplicated, due to the fact that a significant mounting work isrequired for making the hole, fitting and fixing both from the outsideof the hull bottom and from the engine compartment on the inside.

One purpose of the present invention is to achieve a boat hull with anoutboard drive unit of the type described by way of introduction, whichpermits maximally rapid and simple mounting of the drive unit in thehull and where essentially all the work after fitting of the drive unitin the opening in the hull bottom can be done from above, thereby makingit possible to avoid physically tiring up-and-under work.

This is achieved according to the invention by virtue of the fact thatthe opening is so dimensioned that a housing portion joined to theunderwater housing is insertable from below through the opening to aposition on the inside of the hull, that the bottom of the hull isprovided with a well surrounding said opening and extending up into theinterior of the hull, said well being made with an inwardly directedperipheral flange, which, with an elastic insert on each side, is heldtightly between a mounting plate rigidly joined to the underwaterhousing and/or said housing portion and a screw-down plate fastened tothe mounting plate, said plates having shapes adapted to the opening andto the peripheral flange.

The flange and the screw-down and mounting plates may have anon-circular shape and be provided with profiles fitted to each other sothat they can only be mounted in one manner relative to each other. Thescrew-down plate can be provided with peripherally spaced through-boresfor screw-down bolts and the mounting plate may have correspondingthreaded bores for these bolts. After fitting the underwater body in thewell with associated elastic elements abutting against the underside ofthe flange, all that is required is to put the screw-down plate in placefrom above with the second elastic element between it and the flange andto tighten the screw-down plate against the mounting plate with the aidof the bolts.

An outboard drive unit of the type described by way of introduction ischaracterized, according to the invention, in that said mounting meanscomprise a mounting plate rigidly joined to the underwater housingand/or the gear housing, a screw-down plate and elastic inserts forclamping the drive unit against a peripheral flange in a well in thebottom of a boat hull, with the mounting plate and an elastic insert onone side and the screw-down plate and an elastic insert on an oppositeside of the flange.

The invention will now be described in more detail with reference toexamples shown in the accompanying drawings, where

FIG. 1 shows a longitudinal section through a portion of a boat bottomwith a side view of one embodiment of an outboard drive unit withassociated mounting means prior to mounting, and

FIG. 2 shows a corresponding longitudinal section and side-view aftermounting.

In the figures, 1 designates the bottom of a boat hull, which can becast fibreglass reinforced polyester plastic. The bottom 1 of the hullis made with an opening 2 which is surrounded by a vertical well 3,extending up into the interior of the hull. The well 3 is preferablycast in one piece with the bottom 1 and is provided with an inwardlydirected, peripheral flange 4, which, in the example shown, has asubstantially triangular cross section.

The well 3 with the flange 4 forms mounting means for a propeller driveunit generally designated 5, which, in the example shown, has anunderwater housing 6, in which two concentric propeller shafts 7 and 8,respectively, have rotatably mounted individual propellers 9 and 10,respectively. The underwater housing 6 is joined to an upper gearhousing 11, in which a horizontal drive shaft 12 is rotatably mounted.

The shaft 12 is intended to be coupled to a power plant (not shown). Theshaft 12 drives, via a bevel gearing comprising bevel gears 13 and 14enclosed in the gear housing 11, a vertical shaft 15, which in turndrives, via a second bevel gearing having bevel gears 16, 17 and 18enclosed in an underwater housing, the propeller shafts 7 and 8counter-rotationally. In the example shown, the propellers 9 and 10 arepulling propellers disposed forward of the underwater housing 6, in theaft end of which there is an exhaust port 19.

Between the underwater housing 6 and the upper gearing housing 11, thereis, in accordance to the invention, a mounting plate 20 fixed, which canbe cast metal, e.g. aluminium, or moulded fibreglass reinforced plastic.The plate 20 is, as is the well 3, preferably oval in shape inhorizontal projection. The plate 20 has furthermore a conical upwardlyfacing lateral edge surface 21 and the flange 4 has a correspondingconical downwardly directed lateral edge surface 22. By providing theplate 20 and the well 3 with a shape which is non-circular, togetherwith inclined lateral edge surfaces 21 and 22, controlled alignment ofthe drive 5 is achieved relative to the bottom 1 of the hull, when thedrive 5 is mounted from below into the well 3, as illustrated in FIG. 1.

Before the drive 5 with its mounting plate 20 is inserted into the well3, there is placed against the lateral edge 21 of the plate 20 a ring 23of elastic material of e.g. rubber, with a circular cross section andoval shape adapted to the flange 4 and the lateral edges 21, 22 of theplate 20. A screw-down plate 24 with a downwardly facing conical lateraledge surface 25 and an opening 26, which the gearing housing 11 can passthrough, is placed with an intermediate second ring 27 corresponding toring 23 towards an upwardly facing conical lateral surface 28 of theflange. The screw-down plate 24 is then screwed tightly against themounting plate 20 with the aid of bolts 30 disposed in through-bores 29in the screw-down plate 24. Said bolts 30 can be screwed into threadedbores 31 in the mounting plate 20, compressing the elastic rings 23 and27. The thicknesses of the mounting plate 20 and the screw-down plate 24are so adapted to each other that, when the screw-down plate is screwedsecurely to the mounting plate so that the facing surfaces 32 and 33 ofthe plates are in contact with each other, the elastic rings 23 and 27are compressed to a thickness corresponding to a thickness correspondingto the ring radius before being mounted. By virtue of the describeddesign and dimensional relations, the orientation and mounting of thedrives will be completely controlled.

The propeller pulling force is transmitted via the plates 20 and 24, therings 23 and 27, the flange 4 and the well 3 to the boat hull. Theengine, possibly with reverse, is thus freed from the propeller pullingforce and can therefore be mounted on relatively soft vibration-dampingpads. The transmission of vibrations from the drive to the hull isdamped by the elastic rings 23 and 27, of which the lower ring 23 alsoserves as a seal preventing the penetration of water into the well 3.

The invention has been described above with reference to an embodimentwith two separate elastic rings 23 and 27. It is also possible withinthe scope of the invention to use elastic elements on other side of theflange, forming a continuous unit, for example by means of a membrane,which joins the elements to each other. The definition “an elasticinsert on each side” in the attached claims shall be interpreted asreferring either to interconnected or separate elastic inserts.

1. A boat hull with a bottom-mounted drive unit for at least onepropeller, said drive unit comprising an underwater housing extendingdownward from the hull bottom, a drive shaft rotatably mounted in saidunderwater housing, the drive shaft extending through an opening in thehull bottom, a first gear arrangement enclosed in said underwaterhousing coupling the drive shaft to at least one propeller shaft mountedin said underwater housing, and a gear housing portion joined to theunderwater housing, the hull bottom including a well surrounding saidopening and extending into an interior of the hull, said well includingan inwardly directed peripheral flange, wherein the well peripheralflange are manufactured in one piece with the hull bottom, and whereinthe flange has a substantially triangular cross-section, and furthercomprising an elastic insert contacting each side of the peripheralflange, a mounting plate rigidly joined to at least one of theunderwater housing and the housing portion, and a screw-down platefastened to the mounting plate with the peripheral flange therebetween,the elastic insert being held between the mounting plate, peripheralflange and screw down plate, said plates having shapes adapted to theopening and to the peripheral flange.
 2. A boat hull with abottom-mounted drive unit according to claim 1, wherein said elasticinsert comprises upper and lower elastic rings, pressed against an upperand a lower surface, respectively of the peripheral flange.
 3. A boathull with a bottom-mounted drive unit according to claim 2, wherein saidelastic rings in an unloaded state have at least a substantiallycircular cross section and when clamped against the peripheral flangebetween the mounting plate and the screw-down plate are compressed to athickness approximately equal to the radius of the rings in the unloadedstate.
 4. A boat hull with a bottom-mounted drive unit according toclaim 1, wherein the mounting plate is fixed between the underwaterhousing and a the gear housing portion, the gear housing portionenclosing a gear arrangement for coupling the drive shaft to an outputshaft of a motor.
 5. A boat hull with a bottom-mounted drive unitaccording to claim 1, wherein the screw-down plate and the mountingplate are screwed securely to each other by peripherally spaced screwsdisposed inside of said peripheral flange.
 6. A boat hull with abottom-mounted drive unit according to claim 1, wherein the hull bottom,the well and the flange are cast in one piece of fiberglass reinforcedpolyester plastic.
 7. A outboard hull bottom-mounted drive unit fordriving at least one propeller of a boat, comprising, an underwaterhousing in which there is therein a rotatably mounted drive shaft, whichin the operating state of the drive unit, and said drive shaft beingdrivably coupled via a bevel gearing at a lower end by a first peararrangement to at least one propeller shaft mounted in the underwaterhousing, a gearing housing joined to the underwater housing andcomprising a second bearing arrangement drivably coupling via the upperend of said essentially vertical drive shaft is drivably coupled to aninput shaft, and mounting means for mounting the drive unit with theunderwater housing outside and the inside of a boat hull, characterizedin that wherein said mounting well defining an opening in a bottom of aboat hull and having a peripheral flange extending therefrom, a mountingplate rigidly joined to at least one of the underwater housing and thegear housing a screw-down plate disposed on a side of the peripheralflange opposite the mounting plate, and elastic inserts disposed betweenthe mounting plate and the peripheral flange and the screw-down plateand the peripheral flange, the drive unit being clamped against theperipheral flange in the bottom of a boat hull, with the mounting plateand an elastic insert on one side and the screw-down plate and anelastic insert on an opposite side.
 8. The hull bottom-mounted driveunit according to claim 7, wherein two counter-rotatingly driven,concentric propeller shafts with individual pulling propellers aremounted in the underwater housing.
 9. A boat hull with a bottom-mounteddrive unit for at least one propeller, said drive unit comprising: afirst housing extending from an outer surface of the hull bottom; adrive shaft rotatably mounted in said underwater housing and extendingthrough an opening in the bottom of the hull and coupled by a first geararrangement enclosed in said underwater housing to at least onepropeller shaft mounted in said underwater housing; a gear housingportion joined to the underwater housing being insertable from belowthrough the opening in the bottom of the hull to a position inside thehull, the gear housing enclosing a second gear arrangement for couplingthe drive shaft to an input shaft of a motor, wherein, the hullcomprises a well surrounding said opening and extending up into aninterior defined by the hull, said well including an inwardly directedperipheral flange; and, further comprising: a mounting plate rigidlyjoined to at least one of the underwater housing and said gear housingportion and disposed between the underwater housing and the gear housingportion; a screw-down plate fastened to the mounting plate with theperipheral flange therebetween, said plates having shapes adapted to theopening and to the peripheral flange; and, an elastic insert arrangementclamped between the mounting plate and peripheral flange and thescrew-down plate and peripheral flange.
 10. A boat hull with abottom-mounted drive unit for at least one propeller, comprising: anupper substantially flat mounting surface and a lower substantially flatmounting surface formed about a periphery of an opening in the hullbottom; a screw down plate having a substantially flat mounting surface,said screw down plate mounting surface being disposed against and inparallel to said upper mounting surface; an underwater housing extendingdownward from the hull bottom enclosing a rotatably mounted drive shaft,the drive shaft extending downward from the hull, a first geararrangement, and at least one propeller shaft, the first geararrangement coupling the drive shaft to the at least one propellershaft; a gear housing portion joined to an upper side of the underwaterhousing; a mounting plate joined to at least one of the underwaterhousing and the gear housing portion and having a substantially flatmounting surface, the mounting plate mounting surface being disposedagainst and in parallel to said lower mounting surface, wherein, saidscrew down plate and said mounting plate are fastened together with saidupper mounting surface and said lower mounting surface therebetween;and, an elastic insert arrangement disposed between the screw down plateand upper mounting surface and between the mounting plate and lowermounting surface, the elastic insert being deformably compressed betweenopposed parallel mounting surfaces.
 11. The boat hull as claimed inclaim 10, wherein said upper substantially flat mounting surface andsaid lower substantially flat mounting surface are on a flange formed onthe periphery of the hull opening.
 12. The boat hull as claimed in claim11, wherein the flange has a substantially triangular cross-section. 13.The boat hull as claimed in claim 10, wherein said elastic insertcomprises upper and lower elastic rings disposed between the screw downplate and upper mounting surface and the mounting plate and the lowermounting surface, respectively.
 14. The boat hull as claimed in claim13, wherein said elastic rings in an unloaded state have at least asubstantially circular cross section and when clamped against theperipheral flange between the mounting plate and the screw-down plateare compressed to a thickness approximately equal to the radius of therings in the unloaded state.
 15. The boat hull as claimed in claim 10,wherein the mounting plate is fixed between the underwater housing andthe gear housing portion, the gear housing portion enclosing a geararrangement for coupling the drive shaft to an output shaft of a motor.